Coatings known as "two-pack" or two-component systems offer optimal resistance to chemicals and abrasions, as found in our various epoxy products.
Because they incorporate cross-linking chemical reactions between a base (part A) and a catalyst (part B), they must be mixed correctly to ensure high performance.
When you use two-component coatings, be sure to mix each component separately until uniform.
Next, pour the contents of your part B container into your part A container, and blend thoroughly for three minutes with an electric drill, using the spiral mixing blade. This will help prevent air from entering during mixing, which can cause bubbles when you apply your coating.
When finished, move your mixer head up to the surface gently while it is still running. Take care not to remove it completely until it comes to a complete stop.
Sound Mixing Techniques
- Separate your part A and part B containers, and make sure you have one catalyst for every base.
- Use the correct catalyst for your base-double check the TDS and product labels for the correct codes.
- Always mix fully the entire contents of part B into part A.
- Use only the amount of material you plan to use within the specified pot life.
- Use a spiral mixer of proper size, to ensure thorough mixing and mix for three minutes.
- After induction time has elapsed, use your two-component products immediately. If an induction time is not specified, apply immediately after mixing.
Higher temperatures will speed up catalyzing time and decrease the pot life of two-component products. For every additional 10 degrees in temperature, your coating's pot life will generally decrease by half.
The ideal temperature for using these products is 70 degrees Fahrenheit (21 degrees Celsius).
Problems often occur with two-component products when:
- An incorrect part B is mixed with part A.
- You tint the mixture improperly, such as by adding colourant to the combined mixture.
- Products are mixed improperly, such as by agitating too much or too little.
- The induction time and pot life are not followed.
- Products are mixed when the temperature is too high.
Curing and Return to Service
Film curing is the process by which a liquid coating solidifies. With two-component products, this takes place during the chemical reaction between part A and part B.
Most two-component products will dry within several hours. Film curing, however, typically requires seven days to dry. Higher temperatures speed up the curing time, while lower temperatures with high humidity lengthen the time required.
Return to service is shorter for surfaces that receive lighter traffic. The full seven days is usually needed, however, to allow for optimal chemical and abrasion resistance, and for surfaces with higher traffic.
For more information, refer to your product TDS.
Definitions for Two-Component Coatings
- Base (part A): The primary coating, based on polyurethane or epoxy chemistry.
- Catalyst (part B): A chemical ingredient that initiates and accelerates a chemical reaction, without being consumed or modified.
- Curing: The process by which the liquid mixture forms a solid film. The completion of the film-forming reaction results in a fully cured film.
- Film Thickness: The actual thickness of applied film coating. Expressed in wet and dry film thicknesses, it is usually measured in millimeters.
- Induction Time: The amount of time needed for a two-component mixture to sit before it is suitable for application, also called "sweat-in" time.
- Pot Life: The length of time during which a two-component mixture is usable. The pot life includes the induction time.
Benjamin Moore Two-Component Products
- Polyamide Epoxy Metal Primer (KP33)
- Polyamide Epoxy Gloss Coating (KP36)
- Epoxy Mastic (KP45)
- Aliphatic Acrylic Urethane Gloss (KP74)
- Fast Dry Epoxy Sealer/Finish KP41)
- Acrylic Epoxy Gloss (KP43-84 Gloss)
- Acrylic Epoxy Semi-Gloss (KP43-86 Semi Gloss)
- 100% Epoxy Penetrating Sealer/Finish (KP35)
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